A bioterrorist attack, although once thought to be a remote possibility in the United States, is now a very real and terrifying threat to the lives of all Americans. A major area of concern is the distribution and survival of pathogenic bacteria in lakes, rivers, streams, swimming pools, our water supply and soils. Burkholderia pseudomallei (BP) is a Biosafety level 3 pathogen that is normally a saprophyte of soil and water in tropical areas of Southeast Asia, and causes a glanders-like disease called mellioidosis. Mellioidosis can exist as a benign pulmonary form, but may also develop into a rapidly fatal septicemia. If left untreated, >95% of all cases are fatal within 2 days of exposure. According to the US Department of Agriculture, glanders was eradicated from the US animal population in 1934. However, bioterrorists can easily bring such organisms into our country and distribute the organism into many bodies of water, water holding tanks and heavily populated areas where significant aerosols can be produced. Further complicating matters is the fact that bacteria growing as a biofilm are remarkably recalcitrance to biocides and antibiotics. The processes of quorum sensing (QS), a form of cell-cell communication, in the related organism Pseudomonas aeruginosa, is critical for biofilm formation, virulence and resistance to biocides. Because the BP genome harbors homologs to known QS genes, we hypothesize that it, too, participates in QS and uses it for optimal biofilm formation and resistance to biocides. These studies will provide important information that will lead to countermeasures against a potential bioterrorist attack using the potentially lethal gram-negative bacterium, B. pseudomallei. [unreadable] [unreadable]